Karsts, Sinkholes Riddle Southern Monroe County

There is a large sinkhole in Whiteford Union Cemetery in Lambertville, Ned Birkey said.

It’s one of the few in Monroe County on public property, but there are countless similar craters on privately owned farms, forests and fields, particularly in Whiteford Township, Ottawa Lake and Bedford Township.

The sinkhole is evidence of a karst, or underground cavern that forms after years and years of water erosion.

These natural cavities were the main topic of conversation at a presentation hosted Wednesday night by River Raisin Institute at the Sisters, Servants of the Immaculate Heart of Mary, Motherhouse. The talk was attended by Monroe County residents and some teachers.

Mr. Birkey, owner of Spartan Agricultural Consulting and a former Michigan State University Extension agent and Rane Curl of the Michigan Karst Conservancy spoke about karsts around Michigan and Monroe County.

Karsts are common in areas that are rich with limestone. Because of the lack of overburden, or layers of soil, in the area, the karsts are common in the southern portion of the county, Mr. Birkey said.

“The old Lambertville High School on Secor was built on bedrock,” he said, referring to the rock underlying portion of the earth. “There is no overburden. We’ve always tried to document and monitor those areas.”

Danielle Conroyd, executive director of the River Raisin Institute, said her organization offered the discussion in the hopes of educating people and the issues that they can cause, such as contamination and pollution of well water.

Mr. Curl gave a photographic tour of karsts known to or owned by the Michigan Karst Conservancy. Mr. Birkey addressed the same issues in Monroe County specifically.

Mr. Curl said that karsts form as water drains through cracks in limestone bedrock and creates small passages. Those passages grow into caverns and sometimes collapse into sinkholes.

He offered explanations on how to identify karsts visually and the drainage traits that lead to them.

“Some of the caves are large enough to be entered,” Mr. Curl said. “Others have just cracks for entrance that are only big enough for rodents to get through.”

Mr. Curl said that the Michigan Karst Conservancy was created in 1983 to educate Michiganders about karst areas, preserve karsts and conduct scientific studies. His organization gives tours of karsts but discourages people from entering them on their own or trying to climb into sinkholes.

Similarly, Mr. Birkey said a Monroe County division of the conservancy has offered tours of karsts and sinkholes in this area in the early 2000s to government official to point out problem areas. Ms. Conroyd said the institute hopes to arrange similar tours in the fall.

Educating people these problems is difficult in Monroe County.

“But people are worried about other things — their jobs, their kids,” he said. “Since there isn’t a seriously dangerous problem here, it’s easier to overlook.”